bug: weibo home returns HTTP 500 on latest source install

## Summary
After reinstalling `kabi-weibo-cli` from the latest `jackwener/weibo-cli` source, `weibo home --json` still fails consistently with HTTP 500 retries, while other commands like `weibo feed --json`, `weibo profile --json`, and `weibo following --json` succeed.

## Environment
- Install source: latest source from `jackwener/weibo-cli`
- Commit: `ea2e86e0b3c9fb4120660529a60ed7a44b2b90bb`
- Installed via: `uv tool install /tmp/jackwener-weibo-cli`
- CLI version: `weibo, version 0.2.1`
- Platform: macOS (arm64)

## Reproduction
```bash
git clone https://github.com/jackwener/weibo-cli.git /tmp/jackwener-weibo-cli
uv tool uninstall kabi-weibo-cli
uv tool install /tmp/jackwener-weibo-cli

weibo status
weibo home --json
```

## Observed behavior
`weibo status` reports authenticated, but `weibo home --json` retries 3 times and then fails.

stdout:
```text
❌ Request failed after 3 retries
```

stderr:
```text
WARNING:weibo_cli.client:HTTP 500, retrying in 1.5s (1/3)
WARNING:weibo_cli.client:HTTP 500, retrying in 2.2s (2/3)
WARNING:weibo_cli.client:HTTP 500, retrying in 4.4s (3/3)
```

## Additional evidence
These commands succeed in the same environment/session:
```bash
weibo feed --json
weibo profile 2823244085 --json
weibo following 2823244085 --json
```

And `weibo me --json` appears to hit `/ajax/profile/me` with 404 first, then falls back successfully to return profile JSON.

This suggests the failure is specific to the `home` / `friendstimeline` path rather than a global auth or cookie problem.

## Expected behavior
If the session is authenticated, `weibo home --json` should return valid JSON for the following timeline, or at least surface a more structured error if the `friendstimeline` endpoint is unusable.

## Hypothesis
`home` currently calls the `friendstimeline` path directly and has no fallback, while other commands can still work with the same credential set.

Start by running `weibo home --json` and compare its `friendstimeline` request with the successful `feed`, `profile`, and `following` commands. Trace the `home` command's request and retry handling, then verify that an authenticated session returns timeline JSON or a structured error when the endpoint is unavailable.

Written by the indexing model from the issue text.